[$] Time namespaces

The kernel's namespace abstraction allowsdifferent groups of processes to have different views of the system. Thisfeature is most often used with containers; it allows each container tohave its own view of the set of running processes, the network environment,the filesystem hierarchy, and more. One aspect of the system that remainsuniversal, though, is the concept of the system time. The recently postedtimenamespace patch set (from Dmitry Safonov with a lot of work by AndreiVagin) seeks to change that.